1. Field of the Invention
The present invention relates to a medical device having a detachable tip for engaging a tube end, and more particularly to a connection mechanism for attaching a tool-bearing tip to a distal tube end of a surgical or medical device.
2. Background
Medical and surgical instruments such as cauterization tools, laparoscopes, electrified instruments and the like which generally include a tube having a distal end onto which a tip is attached, the tip including a tool for the medical or surgical procedure to be performed, and a proximal end for connection to mechanical and/or electrical systems and which is operated by the surgeon or medical technician performing the procedure, have been widely used because the incision necessary for insertion of such a tool on a medical device is typically small in comparison to alternative methods. As a result of the relatively smaller incision, patients typically exhibit more rapid healing times and often experience fewer complications as a result of surgeries using such medical devices.
A typical medical device of this class may include at least two detachable portions—the tip having the tool as one of the detachable portions, and the tube leading from the distal end back to the proximal end as the other. Further, such medical devices may include an inner tube leading from the proximal end to the tube end of the tube at the distal end for connecting to a yoke which is part of the detachable tip. Because proper operation of the tool on the tip may require precise mechanical shifting of the inner tube and yoke in relation to the tube and housing of the tip, one method that has been used to provide the necessary differentiation when connecting the tip to the tube end has been the use of two sets of threading with mutually differential pitches, respectively on the connections between the yoke of the tip and the inner shaft of the tube end on the one hand, and a housing or casing of the tip and an outer tube of the tube end, on the other hand.
As a result, however, the two threadings of different pitches require fine machining during the manufacturing process, within tolerances that are difficult to achieve using automation and which may tend to increase the cost of manufacturing of such medical devices. For example, after an initial machining of the threading, it may be necessary to test and make adjustments several times by hand, which requires skilled machinists as well as additional iterative steps, which increase the time for manufacture considerably.
Furthermore, the use of threading requires the surgeon or medical technician performing a procedure with the medical device to intricately align the two threadings of different pitch when assembling the tip to the tube end. Such an operation may increase the time necessary to detach and/or reattach tips to tube ends during a medical procedure and therefore increase the costs and medical risks of the medical procedure, for example.
Also, if fluid or other material contaminates the fine threading of the tip or tube end, it may be difficult to adequately clean or sterilize the crevices in the convoluted surface of the threading. Moreover, such contamination may be shielded from autoclaving or sterilization, for example.